AnsweredAssumed Answered

MK20DX128VFM5: USB CDC device not enumerating

Question asked by Hui Shao on Sep 25, 2014
Latest reply on Oct 2, 2014 by Hui Shao



I have problem to make my board enumerated after plugging USB connector into Windows PC. Windows shows nothing after a connection. My configuration is like:


OS: MQX 4.1.1


Tool: IAR and I-jet

BSP: k20d50m

My costumed board is driven by 8MHz crystal and +5v comes directly from PC USB port. The USB ID detection pin is tied to ground and +5V power is seen on the board after connecting to PC. After calculation my board should supply 48MHz to ARM core.

HW wise, how can I debug this issue? I have also post same question on MQX forum(MQX 4.1: USB CDC device "virtual com" not enumerating).

I am asking here to see if I can get HW people help on it.